The remarkable progress that has recently been made in mammalian genetics has been significantly enabled by the development of resources and techniques for efficient genomic analysis. These resources, including highly polymorphic and easily scored genetic markers, large insert clone libraries, genetic mapping panels, and bioinformatics technology, will be relevant for a variety of applications in the individual Projects described as part of this Program. Of particular importance will be the pursuit of genome-wide genotype analysis in the mouse, and gene mapping studies in a number of vertebrate systems. Our laboratory has a great deal of experience in these technologies and will be able to support this Program Project in all aspects of genome analysis. Furthermore, this Genomics Core will have at its disposal sophisticated instrumentation for these studies (including an automated DNA sequencer, robotic workstation, and extensive computing capacity) that have been established as part of a commitment by the Brigham and Women?s Hospital to support state-of-the-art genetic technology.